Mirror mechanisms of the type to which the subject invention generally relates are shown in U.S. Pat. No. 4,523,735 Beck et al; U.S. Pat. No. 3,730,474 Bowers; and U.S. Pat. No. 3,119,591 Malecki all of which inventions are assigned to the assignee of the present invention. The mirror mounting mechanisms of the type to which the aforenoted patents as well as the subject invention relate have come to be termed "Mirror Swing Lock Mechanisms" which generally is intended to describe a mirror mounting mechanism wherein the mirror is normally positioned in a laterally extended position from the vehicle body for normal rear viewing but which mechanism also permits the mirror head support structure to be swung about a pivot axis to a position in which the mirror and its mounting mechanism are generally foldable against the side of the vehicle to prevent the mirror head from being damaged. Such swing lock mechanisms include detent devices which locate the mirror head assembly either in its normally laterally extended position for rearward viewing through the mirror or in its folded back non-viewing position.
In the past, such swing lock mechanisms have been used with larger mirrors of the type used on various types of trucks or heavy vehicles. Such truck mirrors are particularly susceptible to damage since they normally are mounted so as to extend laterally a considerable distance from the vehicle to permit adequate rear view sighting. Such truck mirrors have been subject to being damaged by striking an object either during normal operation of the vehicle or when the vehicle itself is being transported. In either case, it is desirable that the mirror support mechanism fold back against the vehicle side surface under conditions where it either strikes an object or to prevent it from otherwise being damaged during transportation in the vehicle itself. However, such mirror head foldback or swing lock mechanisms are now finding increasing usage with normal vehicles or cars with the same general purpose of preventing damage to the mirror head under conditions likely to cause damage to the head. In any event, the subject invention is not limited to the size of vehicle to which the mirror head is mounted and may be used equally with large and small vehicles.
Particularly as the swing lock for fold back feature becomes more applicable to passenger cars and other small vehicles, prior type mirror swing lock mechanisms have become less than completely satisfactory for numerous reasons. First, there is the ever present demand for less complicated and, therefore, less costly mechanisms. Thus it is applicant's first objective to greatly simplify the swing lock mechanism of the present invention. This inevitably means fewer operating parts and careful selection of coacting swing lock part and, particularly, detent materials. Finally, the swing lock mechanism must function in a way to absolutely minimize vibration of the mirror head when the mirror head is in its laterally outwardly extended position in order to assure a sharp image being viewed in the mirror. It is particularly in this latter respect that the subject invention relates to a substantial improvement over earlier mechanisms.
Another aspect which has become ever increasingly important in realizing an improved swing lock mechanism is attention that environmental matters play in the manufacture of such assembly. In the present device the swing lock mechanism is constructed in a way to eliminate metal to metal contact but also metal to plastic contact and thus eliminates plating or painting requirements in the mechanism. Also eliminated is the need to heat treat previously used metal parts. Basically, the swing lock mechanism involves the coaction between judiciously selected plastic components.